The present research program is to increase our understanding of post-translational enzymatic methylation of free carboxyl groups in proteins. The reaction is catalyzed by S-adenosylmethionine:protein-carboxyl O-methyltransferase (protein methylase II) and neutralizes erythrocyte membrane proteins. The proposed work for the year will be: a) To investigate factors which control the in vivo and in vitro methylation of human erythrocyte membrane proteins. b) To compare the capacity of glucose uptake by methylated and un-methylated erythrocyte ghost membranes. c) To study the biosynthesis of protein methylase II in erythrocyte during the maturation. d) To measure in vivo half life of protein methylase II in erythrocytes.